How to Clean Your Solar Panels

(Last modified on January 26th, 2022.)

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A residential ground mounted solar installation in Santa Barbara, California.

Your solar system has been designed, installed and is producing, now what? If you’ve had your solar panels for a year or more, they could use a cleaning.

We recommend cleaning your solar panels at least once per year. If you notice any kind of debris such as dirt, dust, bird waste, ash from a recent fire, or if you notice your trees have grown and are now partially shading your panels, it’s time to take action! Your solar system can’t generate electricity if they can’t absorb sunlight, so wash your modules regularly, keep nearby plants trimmed and don’t plant anything new where it could cause shading.

We suggest only handling modules while wearing gloves to limit touching the surface with bear hands. Solar panels have an anti-reflective coating on the glass that is very sensitive to fingerprints. Additionally, be sure to never use harsh materials such as scouring powder, steel wool, scrapers, blades, or anything sharp on the glass. Use of such materials will invalidate the product warranty!

Cleaning solar panels is much the same as washing windows. If you would rather, you can ask your window washer to wash your solar array with these special instructions, or reach out to a company that specializes in solar panel cleaning such as Fish Window Cleaning (based in Santa Barbara).

All of the electrical components are secured on the back of the panel and the only part that should be kept clean is the font. Although the glass is tempered to withstand a certain amount of weather, it should never be hosed down on hot days. We highly recommend that you only clean your panels in the early morning or late evening, and never when the sun is at its peak and the modules are still warm.

To wash your solar panels, use non-heated water like from a regular garden hose. Normal water pressure is usually adequate, but you may use water pressurized up to 1500psi if necessary. To remove stains, dirt or other debris, soak the area for about five minutes, and then rinse the panels again and wipe in a circular motion with a soft sponge or seamless cloth to clean. If fingerprints or stubborn marks still won’t budge, then you may add a mild vegetable-based soap.

If you live in a place with “hard” or mineral-rich water, you may want to use a squeegee to dry your panels to help avoid streaking and mineral deposits. And remember, the more regularly you wash them, the lesser the stains and the easier the task will be!

5 thoughts on “How to Clean Your Solar Panels

  1. My system still shuts down every time there is a heavy fog. This has happened consistently since you installed the Sunny Boy inverter. I’ve tried identifying which panel(s) is causing the interruption, but without success. I’ve read there is a device that can identify which panel is the cause. How can I find a service with that capability?

    1. Hi Dennis! Let me have Wesly get back to you on that! He’ll reach out to SMA and see what he can find out.

  2. Thank you for explaining that it’s important to not clean them or hose them down on hot days. I’ve been wondering when a good time might be to get our solar panels cleaned. I’ll have to keep this in mind so we don’t accidentally do anything that might harm them.

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